Contaminated groundwater concerns mount in Minnesota

Groundwater contamination is a growing concern that should be on everyone’s radar, according to MPCA scientists. Three out of four Minnesotans get their drinking water from groundwater sources. However, unlike our lakes, rivers and streams, groundwater is largely out of sight.

“This report underscores the urgent need to ensure that all Minnesotans have clean water," said Governor Mark Dayton. "I look forward to discussing this report, and our state's serious water quality challenges, at the Governor's Water Summit this weekend.”

Where does groundwater contamination start?

Many harmful contaminants enter groundwater from sources like fertilizers, pesticides, urban runoff, septic systems, road de-icing salts, antibiotics, pharmaceuticals and agricultural practices. The cost of cleaning up contaminated groundwater sites is 10 to 30 times more expensive than working to prevent and reduce groundwater contamination. Other contaminants are naturally occurring like arsenic, radium and manganese.

“Groundwater is complicated because it is interconnected to surface water like our lakes, streams and wetlands,” said MPCA Groundwater Monitoring Supervisor, Paul Hoff. “The bottom line is the things we do on land have a huge impact on our groundwater.”

What we know

We know that some contaminants can have far-reaching impacts on the environment and human health. Nitrate is one of the most common contaminants in Minnesota’s groundwater and comes from sources like agricultural fertilizers and animal manure. Up to 60 percent of the groundwater samples from monitoring wells in central Minnesota are contaminated with nitrate well beyond the safe drinking water standard. Drinking water contaminated with nitrate can lead to illnesses such as Blue Baby Syndrome, a fatal blood disorder in infants.

Some of the affected cities include Becker, Clear Lake, Cold Spring, Hastings, Goodhue, Adrian and Park Rapids. City officials in those areas have explored treatment options, including distributing bottled water to residents, drilling new wells, and building new reverse-osmosis water treatment plants. Many small cities are spending millions to address the problem.

Another contaminant, chloride, or road salt, comes from de-icing practices during winter. While chloride is not believed to be very toxic to humans, high concentrations of chloride give drinking water a salty taste many people dislike. The groundwater also may transport toxic levels of chloride to streams and lakes where it can harm fish and other aquatic life.

“Though water with a high chloride concentration isn’t necessarily dangerous, the bulk of complaints received by public utilities are related to the taste and odor of our water,” said MPCA Groundwater Research Scientist, Sharon Kroening.

Cost of clean up

Some Minnesota cities have already experienced the cost burden of treating contaminated groundwater. A 2014 Drinking Water report from the Minnesota Department of Health put cost estimates for treating contaminated drinking water in Minnesota in the billions of dollars.

What are our next steps?

The MPCA partnered with other state agencies with groundwater responsibilities to provide 30 recommendations that will help protect Minnesota’s groundwater. One recommendation includes continuing to fund programs that support clean and safe groundwater, like the MPCA’s Superfund Program. Another recommendation in the report calls for more research to better understand the impacts of contaminants on human health, especially for newer contaminants of concern like pharmaceuticals and antibiotics.

“Groundwater is one of our most precious resources. This report is another warning indicator about our water quality challenges,” said MPCA Commissioner John Linc Stine. “We know that prevention is key. It costs between 10 to 30 times more to fix contaminated groundwater than to prevent contamination in the first place.”